Both in luggage inspection systems in, e.g. airports and in non-destructive testing with penetrating radiation, it is important to provide means and ways whereby it is possible to check whether a given articles has undeniably been inspected. Mostly the inspection with penetrating radiation is secured by means of e.g. forms to be filled out by the inspector, by marking the inspected article, etc. In these cases the marks or forms are not tamper-proof and can more or less easily be forged.
In the field of luggage inspection, it has been proposed to wrap the piece of luggage after X-ray inspection with a plastic foil. A machine wherein the inspection and the wrapping of the luggage proceed directly one after another without the luggage leaving the machine, has been disclosed in, e.g., WO 95/030580.
Although this system secures the inspection by X-ray, it is quite expensive and the wrapped pieces of luggage become more difficult to handle.
In WO 94 16902 the application of labelling an object with two different marks, a visible and an invisible one has been disclosed for secure an object against counterfeiting. A label according to that disclosure is not a tamperproof label capable of securing that an object has been inspected by penetrating radiation.
Therefore there is still a need for a cheap, reliable method to secure the inspection of articles by penetrating radiation.